This is the second trip to the Chrysler service dept in a month for the same problem. While driving from a stop, the auto trans in the "D" (drive) mode, "locks" and starts out in 5th gear. This happened twice & my xfire went to the shop. About three weeks later, while stopped at a traffic light and then driving through the intersection the trans locked in first or second gear. I pulled to the side of the road, shut off the car, restarted & it seemed to shift properly. The next day ... back to the service dept. That was 3 days ago. They have not diagnosed the problem yet. Anyone here having the same problems or any suggestions/advise? Thanks!

 

Sounds bad! But did the XF drive away in the 5th without stalling the engine? Cool! Sorry, in consideration of your problem.
Looks like the shift control is not working properly. Might be because of fault Autostick mode. When the transmission locked in a low gear, did the indicator still show "D" or only "1" or "2"?